Arsenal’s high pressing
Chelsea began the game with possession at the back, where Arsenal caused some early problems through their high pressing.
A typical example starts with Courtois on the ball in open play. Azpilicueta, Kante and Matic in turn are pressured upon receiving the ball. Sanchez blocks the pass to Luiz. Alonso is left free, but is unreachable due to the pressure on the ball. Monreal moves up to close down the space to Moses. Coquelin screens across the front of the backline (pressing Pedro who’s moving deep for the ball) and the rest of the backline shift over.
Chelsea have nowhere to go, especially on the next few tries when Ozil was even able to block the initial pass to Azpilicueta.
As a result, Courtois, while receiving back passes with pressure from Sanchez (blocking the line to Luiz, forcing him to move to try to open a passing line form his goalkeeper), had to find different options. Longer passes to both wing-backs become an option, though one error with a pass to Luiz instead gifts Arsenal the ball in a dangerous situation.
One problem that Arsenal found, as many have this season, was not being able to sustain the high pressing. After the first goal, Arsenal’s pressing began to leave more space for Chelsea to build short and advance. Iwobi and Ozil switching positions freed Azpilicueta in open play and Courtois was also finding David Luiz in space from where he was able to play forward passes.
Chelsea’s wing-backs finding space
Where Chelsea found weakness in Arsenal’s defence was through the wing-backs, especially Moses on the right. He was an outlet to carry the ball up the pitch when the ball was won deep, while when receiving the ball higher up, on knockdowns from Costa for example, he was able to cause Arsenal organisation problems.
The reason behind Moses causing problems when receiving the ball in Arsenal’s half was due to Arsenal not having anyone close enough to him to close him down—Ozil unable to track and the central midfielders too far away to press him early. As a result, Monreal would move up to press him and Pedro would make diagonal runs outside (behind Monreal) into space left by the fullback. Another problem this would then cause Arsenal was that Koscielny would move out to cover Pedro’s run—leaving only two of the back 4 inside the box to defend any potential cross.
In the first situation, when he had Pedro’s movement ahead of him, he dribbled inside and shot. The next time, Monreal was caught between being too high to cover Pedro and too deep to press Moses. Moses played a pass over the top to Pedro, where his attempted pass to Costa inside was blocked.
The third time Moses received the ball in this situation was crucial, as it resulted in the first goal. Hazard joining the box at the near post and Costa as the primary target of the cross drew Mustafi and Bellerin over, leaving Arsenal with two of their back 4 outside of the box and the remaining two both around the near post.
Moses continued to find space throughout the game and use the movements ahead of him to find passes behind to draw Arsenal’s backline out of their box. Alonso also had some success on the opposite flank, with Hazard and Pedro shifting over to make similar runs ahead of the ball.
Arsenal with the ball
When able to press high, Chelsea caused plenty of problems for Arsenal and often managed to force the ball back to Cech to play long. For both the first and third goal the ball was won after pressing the ball back to Cech.
In midfield Arsenal were able to advance past Costa using Koscielny and Mustafi, where Koscielny would normally hold the ball to draw Costa before passing to Mustafi. Mustafi could then advance forward with the ball into midfield, where Chelsea would drop slightly as a block to not press aggressively from the central midfielders (to avoid potentially opening up their block) while Hazard would sometime move up to press him.
Arsenal also changed their positions in possession before and after the goal. Early on they used Iwobi and Chamberlain moving between lines; Walcott on the last line between Alonso and Cahill looking for passes behind; Sanchez leaving the last line to look to receive between the lines; Ozil moving between lines; and the fullbacks up to offer width to their narrow positioning.
After the goal—and being unable to find passes between lines or behind—the midfielders switched to moving outside Chelsea’s block to look for the ball out of pressure and facing play. Iwobi and Ozil switched positions, while Ozil was mostly receiving the ball outside the block with the intention of playing forward—but tight lines continued to prevent central passes. With more players on the outside Arsenal were able to make more use of Mustafi advancing with the ball and drawing Hazard towards him (before finding the pass outside).
When Arsenal lost the ball while in possession in Chelsea’s half, they were usually in bad positions to prevent dangerous counter attacks. With the fullbacks up and Coquelin often the only player near enough to support the midfielders, there were spaces wide and the possibility for Chelsea to overload their backline quickly after winning the ball.
While Chelsea made errors on the ball to prevent creating chances from the initial counters, the opportunities continued to present themselves and they were eventually able to score their second goal through Hazard’s excellent individual run.
An area where Arsenal were able to cause Chelsea problems throughout was on corners. A reason for this was the change to their offensive corners setup upon Bellerin going off for Gabriel. Bellerin was on the edge of the box with Coquelin when he was on the pitch, where Arsenal would have five inside the box (marked man-to-man). During these corners Chelsea had Hazard and Pedro short on the side of the box, along with 3 zonal players spare inside the box: Costa and Kante ahead of the near post, while Moses around the penalty spot in order to be able to press Bellerin or Coquelin if they were to receive the ball.
What changed was that Gabriel moved into the box, Moses switching from zonal to man-to-man in order to pick him up but leaving Coquelin free on the edge of the box. Kante was now the player who would move up to press the edge of the box, but the distance was too far to be able to pressure him early from his deep starting position. From there he was able to have a long shot and cross the ball into the box after a short corner, before Kante (after much consternation on the touchline) switched his starting position from the near post to the position Moses had left to mark Gabriel.
Chelsea caused Arsenal various problems that the Gunners were unable to find solutions to. They were unable to control Chelsea’s wing-backs (which saw them fall behind early on), they couldn’t create with the ball against Chelsea’s compact defensive block, and they were vulnerable to counters every time they lost the ball.